Preheat oven to 375°.
Combine first 5 ingredients in a large bowl; stir gently. Spoon into a 9-inch square baking pan.
Lightly spoon flour into a dry measuring cup; level with a knife. Combine flour and next 5 ingredients (flour through salt) in a medium bowl; cut in margarine with a pastry blender or 2 knives until mixture resembles coarse meal. Add milk, stirring just until moist. Drop dough onto fruit mixture to form 9 mounds; sprinkle with 1 tablespoon sugar. Bake at 375° for 40 minutes or until topping is golden brown.